As explained in the article from Computer World: The vulnerability was introduced by the fix for a hash collision denial-of-service flaw.

It affects a number of Web development platforms including PHP, ASP.NET, Java and Python and can be exploited in a so-called hash collision attack. The PHP development team addressed CVE-2011-4885 in PHP 5.3.9, which was released on Jan. 10.

In short: Stay Safe - Stay Away from PHP. Use the original Perl CMS scripts when and if possible.